Wired and wireless networks, protocols and layers: Wi-Fi

The idea

Wi-Fi is a family of wireless networking technologies that lets devices join a local area network and exchange data through radio waves instead of cables. A device needs a wireless network interface and must associate with an access point, which broadcasts a network name (SSID) and manages traffic. Data is carried on radio channels, and security protocols such as WPA2 or WPA3 encrypt transmissions so that eavesdroppers cannot easily read them. Wi-Fi is convenient because many users can connect without cabling, but signal range is limited by walls and distance, and performance can fall when many devices share one channel. In an exam answer, link Wi-Fi to a specific context, for example a school laptop connecting to a classroom access point, and explain both the benefit of mobility and a limitation such as interference or reduced security compared with a wired link.

What earns the marks

• States that Wi-Fi is a wireless method of connecting devices to a network using radio waves rather than physical cables.
• Explains that a device communicates with an access point, which may broadcast an SSID and act as the gateway to the wider network.
• Identifies that Wi-Fi uses radio channels and that nearby networks or devices can cause interference, reducing reliability or speed.
• Describes security measures such as WPA2 or WPA3 encryption and password protection that reduce the risk of unauthorised access.
• Compares Wi-Fi with wired connections, noting benefits such as mobility and reduced cabling against drawbacks such as limited range and variable performance.

Common mistakes and how to put them right

• Treating Wi-Fi as the internet itself.

  Put it right: Wi-Fi is a wireless local network technology that can provide access to the internet through a router or access point, but the internet is the global network of networks.

• Assuming Wi-Fi is automatically secure because it is wireless.

  Put it right: Security depends on encryption and authentication being enabled, so open networks can allow others to intercept traffic.

• Confusing Wi-Fi with Bluetooth.

  Put it right: Wi-Fi typically connects devices to a local network over longer distances and higher bandwidth, while Bluetooth is a short-range personal area technology for pairing devices.

Exam tips

• Name the context in the question, such as a tablet in a classroom, and apply Wi-Fi to that context rather than giving a generic definition.
• Use correct terminology such as access point, SSID, channel, encryption and interference to show precise understanding.
• When asked to compare, give one advantage and one disadvantage of Wi-Fi against a wired connection, and link each to a consequence for the user or network.